The invention relates to a microscope for the wide-angle viewing of an eye with an optical device provided between the lens and the eye to be treated, and which creates a reversed image for viewing the fundus of the eye, in particular for eye surgeries and, more particularly with an optical device for image reversion and image erection, which device lies in, or preferably can be moved or swung into, the beam or viewing path of the microscope.
A wide-angle viewing of the eye can take place in a simple manner through the use of a contact lens placed directly onto the eye. However, it is also possible to mount a separate optical device, which is spaced from the eye, on the microscope. If aspheric lenses are used for this purpose, which lenses guarantee alone a sufficient wide-angle viewing, then a side-reversed, upside-down image is created in the microscope just as this is the case with the contact lens, which image is acceptable for diagnostic purposes; however, during eye surgeries, which must be carried out advantageously at least at times also with a wide-angle viewing under stereo observation, a reversed stereopsis is created so that even experienced surgeons cannot be expected to handle such a control technique.
It is also already known to provide in such a microscope a device for the image reversion and image erection, as this is shown in the DE Patent No. 38 26 069 C2 (corresponding to U.S. Pat. No. 5 009 487). It is thereby particularly important that the additional structural parts do not significantly increase the height of the microscope because the surgeon must carry out the surgery and must look through the microscope at the same time, and the distance between the eyepiece of the microscope and the eye of the patient can therefore not be increased at random. Furthermore, the optical device for image reversion and image erection is, however, also supposed to be moved is quickly as possible into and out of the beam path of the microscope so that work can be done both in the front section of the eye and also in the fundus of the eye without having to change the microscope.
The purpose of the invention is therefore to design a microscope of the type identified in greater detail above so that its height does not significantly increase not even when it can be operated selectively with an optical device for image reversion and image erection.
The purpose is attained according to the invention in such a manner that the optical device for image reversion and image erection consists of a reflecting system with a low height in particular a prism system which is carried by a bolder fastened on the microscope, and can thus be moved or swung into the beam path of the microscope between the lens and the eye to be treated, that the prism system is provided directly in front of the lens at a distance from the eye. The arrangement of the invention utilizes the space existing between the lens and the eye to be treated so that the total overall height of the microscope is maintained even when a non-reversed and upright image is created in the eyepiece. It is thereby of no importance in which manner the wide-angle viewing is produced: the optical device for viewing the fundus of the eye can both be mounted on the holder for the prism system and can also be designed to be placed directly onto the eye. A non-reversed and upright image is in this manner created immediately after the swinging in or moving in of the optical device, which image must not be created only after a further operation. In other words, manual or foot operation otherwise needed for this is eliminated, which is of a great advantage especially during eye surgery.
The optical device for the image reversion and image erection can be inserted into the area between the lens and the eye. However, it is significantly easier when the holder is rotatable about a swivel axis arranged on the underside of the microscope so that only a few parts are needed in order to swing the optical device from a position ready to operate into the beam path of the microscope. The prism system is thereby preferably arranged in a closed housing which has openings therethrough for the beam path. In addition, a projection lens for adjusting the beam path can be provided between the prism system and the lens, preferably in the opening of the housing adjacent to the lens, which projection lens is directly adjacent to the lens after the holder for the prism system has been moved or swung into the beam path of the microscope. Moreover it is advantageous when the swivel axle for the holder is provided approximately horizontally on the microscope. In other embodiments the swivel axle can be oriented vertically.
The optical device for the (wide-angle) viewing of the fundus of the eye can consist of a lens system movably arranged along the beam path. The distance of this lens system from the eye can be left unchanged by the surgeon during his work when for focusing a movable optical device is provided in the beam path between the optical device for viewing the fundus of the eye and the prism system, which optical device is movable along the beam path and relative to the prism system; one single optical lens, which itself can be focused, is already sufficient for this purpose.
It is advantageous when for focusing both optical devices can be operated for wide-angle viewing and/or for adjusting the intermediate image by means of manually or electromotively driven spindle drives. Thus it is, for example, possible to move the optical device for viewing the fundus of the eye by means of a first spindle drive fastened on the holder along the beam path, best in such a manner that the optical device is held on a carriage which is guided longitudinally movably on a guide pin mounted on the holder and extending parallel to the first spindle drive, whereby a first control knob for the first spindle drive is supported on the guide pin. The entire adjustment mechanism for the optical device is in this manner connected to the holder and thus also to the prism system, and is at all times exactly adjusted.
The optical device for adjusting the intermediate image can be handled in a similar manner when same can be moved along the beam path by means of a second spindle drive fastened on the guide pin, whereby a second control knob is used for this purpose.
The prism system can be designed, for example, as a reflection prism according to Uppendahl or Schmidtpechan.
The control knobs for the spindle drives can be manually operated; however, they can be operated in an advantageous manner by means of an electric drive, whereby such a drive has, for example, an electric motor preferably provided on the holder, the output of which electric motor can be rotationally coupled to the control knob through a flexible shaft so that the switching on and off can be done, if desired, with a foot-operated switch so that the surgeon will be able to keep his hands free when refocusing must take place.